A big issue is the cost of Bismuth. It was 5$/lb in Dec 06, around $16/lb in Sept 07 and is now around $11/lb.
Manufacturing bismuth shot is difficult because it needs to be cast instead of dropped from a shot tower as with lead.
Sooo, at $16/lb that is $1 per oz, for the RAW METAL... So you can at least double that for finished shot (not loaded shells)
So if someone is selling Bismuth shot at a gun show for less than $150 for the 7 lb containers, it would be a great deal....
Note, I am now shooting Kent Tungsten Matrix for my nice old shotguns.
Now, if you are still looking for a manual for loading Bismuth Shot, go to Precision Reloading